Bore evacuator for cannons



Jalvzl, 1954 A. A. CAMPIONE ETAL 3,118,342

BoRE EvAcuA'roR FOR cANNoNs Y Filed June 11, 1962 s sheets-sheet 1 Jan. 2l, 1964 A. A. CAMPIONE ETAL 3,113,342

BoRE EvAcUAToR FOR cANNoNs Filed June 11, 1962 5 Sheets-Sheet 2 llll a2 ma INVENTORS I:

A. A. CAMPIONE ETAL 3,118,342

Bom: EvAcuAToR FOR cANNoNs Jan. 21, 1964 5 Sheets-Sheet 5 Filed June l1, 1962 INVENTORS lfra c1 A Efnrnpnne Herm-n.11 .Tnbun sky United States Patent() 1 3,118,342 BORE EVACUATR FOR CANNONS Alfred A. Campione, Rotterdam, and Herman A. Tobensky, Colonie, N.Y., assignors to the United States of America as represented bythe Secretary of the Army Filed .lune 11, 1962, Ser. No. 201,741 3 Claims. (Cl. 89-1) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to artillery type guns and more particularly to bore evacuators therefor.

It is very important with those artillery guns in which the breech opens into an inclosed area, as in a tank, that means be provided for evacuating the fumes from the tube bore as the breech is opened to load another round so that the operators in the inclosed area will not be overcome by the noxious fumes.

:The present evacuator used on howitzers contains a fiapper type gating system consisting of multiple springs with a back up ring used as a stop. This requires a total of twelve orifices in the tube and six iiapper valves, and the machining tolerances are quite close. In addition, to remove the moisture in the evacuator reservoir and to clean the functioning parts the muzzle brake and the evacuator assembly have to be removed from the tube.

It is the object of this invention to provide a bore evacuator which requires only three orifices and valves and in which the functioning parts may be cleaned and the collected moisture drained from the reservoir without having to remove the evacuator.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. l is a reduced perspective view of a howitzer with the evacuator mounted on the firing tube;

FIG. 2 is a longitudinally cross-sectioned view of the evacuator showing the valve in its normal position;

FIG. 3 is an enlarged longitudinally cross-sectioned view of the valve assembly mounted in the evacuator reservoir and shows the valve unseated by superior pressure in the bore of the firing tube;

FIG. 4 is a view taken along line 4-4 of FIG. 2; and

FlG. 5 is an exploded perspective view of the valve assembly.

Shown in the figures is a howitzer 12 having a firing tube 14 with a bore 16, a breech closure member 17 actuated between a breech open and a breech closed position and an evacuator 18 mounted on the firing tube near the muzzle end. Evacuator 18 includes a cylindrical reservoir 20 with a rearwardly sloping rear end wall 22 and openings at the front and rear ends for receiving firing tube 14. The front and rear ends of reservoir 20 are sealed gas tight relative to the outside surface of firing tube 14 by conventional means which also prevent displacement of the reservoir relative thereto.

Three ports 21 are provided through wall 22 so as to be symmetrically disposed 120 degrees apart and a bushing 24 is fixedly mounted in each of the ports. Bushing 24 is provided with a stepped cylindrical hole 26 the central axis of which is related to the central axis of bore 16 at about a 30 angle. Three apertures 28 are provided through the wall of firing tube 14 so as to have communication with bore 16 and each of the apertures is located in coaxial alignment with hole 26 in the respective one of the bushings so that the apertures are located within the confines of reservoir 2t) and incline forwardly and inwardly from the outside of the firing tube to the bore therein.

Mounted in each of the related pairs of the bushings 24 ICC and the apertures 28 is a valve assembly 29 having a case 3th with a threaded stem 32 of reduced diameter at the front end and a stepped axial bore including a larger diameter section 34, which extends from the rear end of the case to an annular shoulder 36, and a smaller diameter section 38 which extends from such annular shoulder through the stern to the front end of the case. A plurality of vents 40 extend through case 30 at larger diameter section 34 and the inside edge of shoulder 36 is beveled to form a valve seat 42.

Slidingly mounted inside of case 30 is a valve 44 having a tapered head 46 the larger diameter section of which is approximately the same as that of section 34 and which is formed to make gas tight contact with valve seat 42 when pressed thereagainst. A shaft 47 of smaller diameter extends rearwardly from head 46 and an orifice 48 extends axially through the entire length of valve 44. A plug 50 is threadingly installed in the rear end of case 30 and is fixed against angular displacement relative thereto by means of a pin 52 mounted transversely through the plug and case. A plurality of beveled washers 53 are stacked in case 3l) between plug 5l) and valve 44 so that the end of shaft 47 contacts the front one of the washers when head 46 is fully unseated and a compressible coil spring 54 is disposed in the case between the washers and the rear end of head 46 so as to bias the valve into contact with valve seat 4Z. The end of shaft 47 is arranged t0 Contact the front one of the washers 53, to absorb the impact of valve 44 caused by the rapid rearward displacement thereof, before spring 54 bottoms.

Each of the valve assemblies 29 is inserted through one of the bushings 24 so that the front end of case 30 is received by the related one of the apertures 28. Apertures 28 are each provided with a threaded smaller diameter portion 56 for threadingly receiving stem 32 and a larger diameter portion 58 for receiving the front end of the case rearwardly of the stem, as shown in FIG. 3.

The rear end of hole 26 in each of the bushings 24 is counterbored and threaded for threadingly receiving a cap 60 which is provided with a cylindrical recess 62 in the front end for receiving the rear end of valve assembly 29. A set screw 64 is mounted axially through the end of cap 60 so that it may be manually tightened against the end of plug 5t) to prevent the unloosening of the valve assembly.

When howitzer 12 is fired and the energized shell, noted at 66, passes apertures 28, the compressed gases behind the shell pass through the apertures to impinge upon that portion of valve head 46 exposed to the action of the gases in section 38. The action of the gases causes valve 44 to be displaced rearwardly in case 3l) and thereby permits the free and rapid passage of the compresses gases into the case and out through vents 40 into reservoir 20.

When the pressure in bore 16 and the inside of reservoir 20 are approximately equal, valve 44 is returned by force of spring 54 into contact with valve seat 42. When the pressure in bore 16 is reduced by the passing of shell 66 from bore 16, the gases stored in reservoir 20 are jetted back into the bore through the orifices 48. Because of the inclination of the orifices 48 relative to the central axis of bore 16, the gases discharged from the orifices drive the residual gases in the bore forwardly of the apertures out of the muzzle end of the bore and produce a low pressure area in back of the apertures to flow the remaining residual gases in the bore forwardly out of firing tube 14 when breech closure member 17 is opened. The diameter of the orifices 48 is arranged so as to prolong the discharge of the trapped gases from reservoir 20 for a sufficient length of time to permit the convenient opening of breech closure member 17.

The functioning parts of evacuator 18 are all contained within the valve assemblies 29 which are easily removed for cleaning by removing the caps 60 and the inside of reservoir 20 may be easily drained of collected moisture by removing the bottom one of the valve assemblies and elevating the angle of ring tube 14.

From the foregoing it is readily apparent that there is provided herein a bore evacuator which is easily cleaned and serviced and which is simple but rugged in construction and positive in operation.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

We claim:

1. A gun having a firing tube with a bore, a breech closure member actuatable between a breech open and a breech closed position and a bore evacuator mounted on said firing tube, said evacuator including a reservoir for storing gases under pressure, a plurality of apertures formed in said tube for passing compressed gases therefrom into said reservoir at a rapid rate of iow, a plurality of valve assemblies equal in number to said apertures, each of said valve assemblies being arranged for cooperation with a related one of said apertures to admit discharge gases into said reservoir at a rapid rate and to release the gases from said reservoir into said bore at a reduced rate and in a direction relative to said bore to cause forward evacuation of the gases remaining therein when said breech closure member is actuated to the breech open position, and means for mounting said valve assemblies through said reservoir from the outside thereof into cooperation with the related one of said apertures.

2. The gun as defined in claim 1 and including a threaded stern portion provided at the front end of each of said valve assemblies, a threaded portion arranged in each of said apertures for threading engagement with said stem of the related one of said valve assemblies, and a cap arranged for threading engagement with each of said means from the outside of said reservoir for receiving the rear end of the associated one of said valve assemblies.

3. The gun as defined in claim 1 wherein each of said valve assemblies includes a hollow case having a stem formed at the front end so as to be received for threading engagement with one of said apertures, means for passing gases at a rapid rate from said bore through said case and into said reservoir, a valve arranged for Contact with a valve seat inside of said case and to be unseated therefrom by gases passing from said bore into said reservoir to permit the rapid flow of gases thereinto, spring means for biasing said valve into contact with said valve seat when the gas pressure in said reservoir is greater than that in said bore, an orice formed in said valve for discharging the gases from said reservoir back into said bore at a slower rate of flow, and wherein each of said means is related to the associated one of said apertures so that the one of said valve assemblies mounted therebetween is positioned so that the gases discharged by said orifices into said bore cause forward evacuation of the gases remaining thereon when said breech closure member is actuated to the breech open position.

References Cited in the le of this patent UNITED STATES PATENTS 2,791,940 Speake et al. May 14, 1957 2,807,986 Howard et al Oct. 1, 1957 FOREIGN PATENTS 71,372 Austria June 26, 1916 

1. A GUN HAVING A FIRING TUBE WITH A BORE, A BREECH CLOSURE MEMBER ACTUATABLE BETWEEN A BREECH OPEN AND A BREECH CLOSED POSITION AND A BORE EVACUATOR MOUNTED ON SAID FIRING TUBE, SAID EVACUATOR INCLUDING A RESERVOIR FOR STORING GASES UNDER PRESSURE, A PLURALITY OF APERTURES FORMED IN SAID TUBE FOR PASSING COMPRESSED GASES THEREFROM INTO SAID RESERVOIR AT A RAPID RATE OF FLOW, A PLURALITY OF VALVE ASSEMBLIES EQUAL IN NUMBER TO SAID APERTURES, EACH OF SAID VALVE ASSEMBLIES BEING ARRANGED FOR COOPERATION WITH A RELATED ONE OF SAID APERTURES TO ADMIT DISCHARGE GASES INTO SAID RESERVOIR AT A RAPID RATE AND TO RELEASE THE GASES FROM SAID RESERVOIR INTO SAID BORE AT A REDUCED RATE AND IN A DIRECTION RELATIVE TO SAID BORE TO CAUSE FORWARD EVACUATION OF THE GASES REMAINING THEREIN WHEN SAID BREECH CLOSURE MEMBER IS ACTUATED TO THE BREECH OPEN POSITION, AND MEANS FOR MOUNTING SAID VALVE ASSEMBLIES THROUGH SAID RESERVOIR FROM THE OUTSIDE THEREOF INTO COOPERATION WITH THE RELATED ONE OF SAID APERTURES. 